This invention relates generally to compositions for dissolving paint. More specifically, it relates to a composition which can solvate a wide variety of dried paints at room temperature.
Painting is an important step in the manufacture of a wide variety of articles. In a mass production setting, painting is often carried out by high speed processes such as spray painting or dip coating, wherein workpieces are sequentially carried through a series of painting stations. The cleaning of dried paint residues from conveyors, carriers and paint station equipment is a significant and ongoing concern of manufacturers. This problem is further compounded by the fact that in the manufacture of motor vehicles and many other items, a number of different paint formulations are employed. For example, automobiles are typically coated with one or more primer layers, a base color layer, and a top clear coat. These various paint formulations are often very different in composition and may be provided by a number of different suppliers. As a consequence, the cleaning of dried paint films from such equipment can be very difficult, since the solubility properties of the various dried paint films can differ to a very large extent.
It will be understood from the foregoing that there is a need, in the manufacturing industry, for a solvent material which is capable of dissolving dried films of a variety of paint compositions. It is also necessary that any such composition be relatively low in toxicity, safe to handle, and non-damaging to the equipment.
It is a significant feature of the present invention that the compositions have xe2x80x9cuniversalxe2x80x9d applicability; that is to say, the compositions of the present invention are capable of dissolving a wide variety of dried paints including water-based and solvent-based formulations, primers, base coats, clear coats and metallic paints. It is also significant that the present compositions will effectively dissolve paints at ambient temperatures. Prior art compositions are generally capable of only addressing relatively narrow ranges of paint compositions; and as a consequence, a manufacturer often needed to employ a large number of different compositions in a manufacturing process. Furthermore, prior art compositions often had to be used at elevated temperatures in order to be effective. Thus, it will be seen that the present invention secures a number of advantages not achievable in the prior art.
The compositions of the present invention can be formulated with volatile organic compound (VOC) exempt solvents such as acetone, methyl acetate and the like.
In addition, the compositions of the present invention are rinsible with water or solvents and are fast acting. As a result of the foregoing, compositions in accord with the present invention have particular utility for cleaning painting equipment used in the manufacture of motor vehicles. Such equipment typically includes a large number of separate paint delivery lines, pumps, tanks and the like. Compositions of the present invention can be pumped through paint delivery systems, and they reliably remove all paint residues therefrom. Following cleaning, the compositions can be easily rinsed from the paint delivery systems. The compositions of the present invention actually dissolve paint residues, and as such have greater utility than do paint stripper compositions which merely swell and lift paint films.
There is disclosed herein a universal paint solvent which comprises, on a weight basis, 1-30% of an acidic material which is selected from the group consisting of sulfonic acids, phosphonic acids, phosphoric acids, and combinations thereof. The composition further includes 10-80% of an organic solvent which is selected from the group consisting of alcohols, esters, ketones, aldehydes, ethers, aromatic hydrocarbons, and combinations thereof. The composition may also include, on a weight basis, up to 10% of an additive selected from the group consisting of: amine ethers, surfactants, and combinations thereof. In specifically preferred embodiments, the acidic material is comprised of a mixture of two different acidic materials, and in one specific group of formulations, the acidic material is comprised of a mixture of a toluene sulfonic acid and a xylene sulfonic acid. The organic solvent, in particular embodiments, comprises an alkyl ester; which in specifically preferred embodiments comprises an ester of a C1-C5 acid and a C1-C5 alcohol. Butyl acetates comprise one particularly preferred ester, with n-butyl acetate being specifically preferred.
Also disclosed herein are methods for dissolving paint from articles, including paint delivery systems. The method comprises contacting the article with the universal paint solvent of the present invention. It is notable that the method may be practiced at room temperature, which in the context of this disclosure is understood to mean a temperature in the approximate range of 40xc2x0 F. to 120xc2x0 F.